The present invention relates to a joint and is specifically concerned with a joint for securing a tubular member to a support member.
Certain structural configurations may require that a tubular member be secured to a support member. By way of an example, the tubular member could be an extruded metal element while the support member could be a formed metal bracket or plate. A specific application for this type of a joint involves the construction of a seat wherein a tubular metal frame for the seat back is formed into a generally inverted U shape configuration. Spaced apart metal brackets, or plates, are provided at the base of the seat back and it is necessary for the ends of the inverted U-shaped tube to be secured to these metal brackets.
A previous construction for this joint involved mounting weld nuts in the sidewall of the tube adjacent the tube ends. A clearance hole is provided in the tube wall opposite each weld nut. The tube is assembled to the brackets by placing each clearance hole in the tube in alignment with a corresponding hole in the attaching bracket and then running a screw through the bracket hole, through the clearance hole in the tube sidewall, across the inside of the tube and into the weld nut in the far portion of the tube sidewall. As the fastener is torqued, the tube is drawn against the mounting bracket.
The previous procedure described in the preceding paragraph is disadvantageous from the standpoint that separate elements, i.e. the weld nuts, must be assembled to the tube. The tube must also be processed beforehand to provide the necessary clearance holes as well as to provide for the mounting the weld nuts to the tube.
The present invention is directed to a new and improved joint for securing a tubular member to a support member. The invention is particularly advantageous in the context of mounting a tubular seat back to attaching brackets, although it will be appreciated that principles of the invention are applicable to other specific embodiments. One significant advantage of the invention is that it eliminates the requirement for mounting weld nuts on the tubular member. This yields economy in the fabrication of the tubular element. A further benefit of the invention is that an improved, more secure joint construction is obtained with the present invention. Hence with the invention a more economical yet sturdier joint results.
Briefly the invention, in its preferred embodiment,comprises a pair of aligned extruded holes in the sidewall of the tubular member opposite each other, a clearance hole in the support member aligned with the extruded holes of the tubular member, and a self-tapping screw engaging the support member and passing through the hole in the support member with the shank of the self-tapping screw threadedly engaging complementary threads in both of the extruded holes which were cut by the self-tapping screw during the process of fastening of the two members together by means of the screw. As a consequence the holding force between the two members is concentrated between the abutting portions of the support member and the tubular member. This is in contrast to the prior weld nut construction wherein the holding force is applied at the far opposite sidewall portion of the tube containing the weld nut. Consequently, the invention provides a studier joint with increased holding force.
In connection with the present invention a novelty search was conducted in the United States Patent and Trademark Office and the following patents were developed: Nos. 1,962,035; 1,926,686; 1,951,839; 2,062,685; 2,234,097; 3,362,737; 3,869,219; 3,414,304.
The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawing. The drawing discloses a preferred embodiment of the invention according to the best mode contemplated at the present time for carrying out the invention.